FIG. 1 is a section view of a contact type image sensor according to the relevant technology. As show in FIG. 1, the structure of the contact type image sensor used for reading image by the relevant devices, such as multifunctional all-in-one machine, special scanner and fax machine is as follow: a glass plate 3 is arranged on a framework 1; a circuit board 5 is arranged below the framework 1; a set of photoelectric conversion chips 6 are arranged on the circuit board 5; a set of linear array lenses 4 are arranged on the photoelectric conversion chips 6; a light source 2 is arranged on one side of each linear array lens 4. Each light source of the contact type image sensor emits light on one side of the corresponding linear array lens, and the light sources only supply one light emitting direction.
With the expansion of the application field, more and more requirements are made on the functions of image sensor. For example, a paper money counterfeit detection machine of a bank system needs to recognize multiple pieces of anti-counterfeit information on paper money, wherein hologram information needs to recognize different pieces of image information at different angles or directions. Generally three different images may be observed on holograms on the current paper money in the world at different angles or directions.
For the problem that the device for recognizing the image in relevant technology may only supply one single light emitting direction, no effective solution is provided at present.